package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {
    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private RedisIdWorker redisIdWorker;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;
    //初始化lua脚本
    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    //加载lua脚本
    static{
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }
    //创建线程池，实行订单的存储
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();
    //初始化
    @PostConstruct
    public void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }
    private class VoucherOrderHandler implements Runnable {
        String queueName = "stream.orders";
        @Override
        public void run() {
            while (true) {
                try {
                    //1.获取消息队列中的订单信息
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    //2.判断消息队列中的元素获取是否成功
                    if(list == null || list.isEmpty()){
                        //2.1不成功，说明没有消息，进行下一次循环
                        continue;
                    }
                    //3.解析消息队列中的数据
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    //true 参数表示即使某些字段名称不完全匹配，也可以尝试进行映射
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //4.如果获取成功，可以下单
                    handleVoucherOrder(voucherOrder);
                    //5.ACK确认
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while (true) {
                try {
                    //1.获取pending-list中的订单信息
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    //2.判断消息队列中的元素获取是否成功
                    if(list == null || list.isEmpty()){
                        //2.如果获取失败说明pending-list没有异常消息，结束循环
                        break;
                    }
                    //3.解析消息队列中的数据
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    //true 参数表示即使某些字段名称不完全匹配，也可以尝试进行映射
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //4.如果获取成功，可以下单
                    handleVoucherOrder(voucherOrder);
                    //5.ACK确认
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理pending-list订单异常", e);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException ex) {
                        throw new RuntimeException(ex);
                    }
                }
            }
        }
    }
    //创建一个阻塞队列，（阻塞队列：当队列中没有元素时队列就被阻塞了）
    /*private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024*1024);
    //创建线程，执行订单存储
    private class VoucherOrderHandler implements Runnable {
        @Override
        public void run() {
            while (true) {
                try {
                    //1.获取队列中的订单信息
                    VoucherOrder voucherOrder = orderTasks.take();
                    //2.创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (InterruptedException e) {
                    log.error("处理订单异常", e);
                }
            }
        }
    }*/
    //通过异步线程进行操作
    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        //1.获取用户Id
        Long userId = voucherOrder.getUserId();
        //2.创建锁对象
        RLock lock = redissonClient.getLock("lock:user:" + userId);
        //3.获取锁,设置超时时间
        boolean isLock = lock.tryLock();
        //4.判断获取锁是否成功
        if(!isLock){
            //返回错误信息
            log.error("不允许重复下单");
            return;
        }
        try {
            //利用当前spring代理对象，调用方法,防止事务失效
            proxy.createVoucherOrder(voucherOrder);
        } finally {
            //释放锁
            lock.unlock();
        }
    }
    private IVoucherOrderService proxy;
    @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户Id
        Long userId = UserHolder.getUser().getId();
        //获取订单id
        long orderId = redisIdWorker.nextId("order");
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString(),
                String.valueOf(orderId)
        );
        //2.判断返回结果是否为0
        int intResult = result.intValue();
        if(result != 0){
                //2.1不为0返回异常信息
               return Result.fail(intResult == 1 ? "库存不足" : "不能重复下单");
        }
        //3.获取当前spring代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //4.返回订单Id
        return Result.ok(orderId);
    }
/*    @Override
    public Result seckillVoucher(Long voucherId) {
        //1.查询优惠券信息
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        //2.判断秒杀是否开始
        if(voucher.getBeginTime().isAfter(LocalDateTime.now())){
            //3.否，返回尚未开始
            return Result.fail("秒杀尚未开始");
        }
        if(voucher.getEndTime().isBefore(LocalDateTime.now())){
            //3.否，返回尚已结束
            return Result.fail("秒杀已结束");

        }
        //4.是，判断库存是否充足
        if(voucher.getStock()<1){
            //5.否，返回异常结果
            return Result.fail("库存不足");
        }
        Long userId = UserHolder.getUser().getId();
        //1.创建锁对象
        //SimpleRedisLock lock= new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        RLock lock = redissonClient.getLock("lock:user:" + userId);
        //2.获取锁,设置超时时间
        boolean isLock = lock.tryLock();
        //3.判断获取锁是否成功
        if(!isLock){
            //返回错误信息
            return Result.fail("不允许重复下单");
        }
        try {
            //获取当前spring代理对象
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            //利用当前spring代理对象，调用方法,防止事务失效
            return proxy.createVoucherOrder(voucherId);
        } finally {
            //释放锁
            lock.unlock();
        }
    }*/
    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        //7.一人一单的判断
        Long userId = voucherOrder.getUserId();
        //加锁
            //7.1获取用户id
            //7.2查询voucherOrder表，判断用户是否已经购买过该优惠券
            int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
            if (count > 0) {
                //表示该用户已经下过单了
                log.error("用户已经购买过该优惠券");
                return;
            }
            //6.是，扣减库存  (添加乐观锁防止超卖)
            boolean success = seckillVoucherService.update().setSql("stock=stock-1")    //set stock=stock-1
                    .eq("voucher_id", voucherOrder.getVoucherId()).gt("stock", 0)    //where id=? and stock>0
                    .update();
            if (!success) {
                //扣减失败
                log.error("库存不足");
                return;
            }
            save(voucherOrder);
        }
    }
